System for real-time device data management

ABSTRACT

A real-time device data management (RTNDD) system for managing access to data describing devices in a telecommunications network. The RTNDD system maintains a partition data structure for each device. The partition data structure has a header section and a port data section. The header section contains data elements describing the device (e.g., number of ports and device type). The port data section has a port data structure for each port of the device that contains data elements describing the port (e.g., current cross-connect and actual port address for device). The RTNDD system also provides a standard interface through which external systems access the device data. The standard interface has functions for reading and writing to the partition data structures. Each read function reads multiple data elements of a header section or a port data structure at a time, and each write function writes a single data element of a device at a time. The standard interface is device independent such that an external system can use the standard interface to access device data for any type of device whose data is stored in a partition data structure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a Divisional Application of U.S. patentapplication Ser. No. 08/777,464 filed on Dec. 30, 1996, now U.S. Pat.No. 5,909,682.

TECHNICAL FIELD

The preferred invention is related generally to communication networksand, in particular, to the storing of data to describe the network.

BACKGROUND OF THE INVENTION

In the telecommunications field, telecommunications carriers (e.g., longdistance providers) continually strive to increase the reliability oftheir telecommunications networks. A telecommunications network consistsof a collection of network nodes interconnected via transmission lines.Traffic is transmitted on the network from one endpoint to anotherendpoint through a current route, which is a network path that specifiesthe transmission lines that interconnect the endpoints. The main path(i.e., trunk) through the network is referred to as the original route.The network nodes may serve a variety of functions such as amplifyingthe network traffic for transmission down the next transmission line inthe route or establishing an interconnection between two transmissionlines connected to the node (i.e., a switch). Unfortunately, thecomponents (e.g., nodes and transmission lines) of the transmissionnetwork may occasionally fail. For example, a transmission line that isa buried fiber optic cable may fail as a result of being inadvertentlysevered by someone digging near the buried cable.

If one or more of the cables fail, massive disruption of services to alarge number of network customers could result. Therefore,telecommunications carriers strive to quickly and economically route thenetwork traffic around such failed components by establishing a"restoral" route. A restoral route is a portion of a path between theendpoints that does not include the failed component. The establishingof a restoral route generally involves: (1) detecting that a componenton the current route has failed, (2) identifying the location of thecomponent, (3) selecting a restoral route to bypass the failedcomponent, and (4) implementing the selected restoral route. Thereliability of telecommunication networks depends in large part on theability to detect such failures and implement the restoral route withminimal impact on network customers.

Telecommunications carriers typically develop "pre-planned" restoralroutes that are used when various components fail. The development ofsuch pre-planned restoral routes has several disadvantages. Onedisadvantage is that the amount of time needed to develop the restoralroute for the network can increase exponentially with the size of thenetwork. To develop the restoral routes, a telecommunications carriertypically collects large amounts of data relating to thetelecommunications network. This data can include the topology of thenetwork, speed of network components, and relative costs of the networkcomponents. A network analyst then analyzes the collected data andidentifies the pre-planned restoral routes that would result in minimalimpact on network customers both in terms of cost and service. Theanalyst typically needs to identify a pre-planned restoral route foreach component that could possibly fail. A second disadvantage is thatthe pre-planned restoral routes cannot realistically take intoconsideration every possible combination of component failures. Thus,the pre-planned restoral routes may not be an optimal restoral routegiven the combination of failures that have occurred. A thirddisadvantage is that the pre-planned restoral routes cannot adjust tothe dynamic nature of the network. The topology of a telecommunicationnetwork can be dynamic, that is components can be added, removed, andchanged frequently. Therefore, these pre-planned restoral routes mayfail because they were developed from outdated data. Consequently, eachtime the topology changes new pre-planned restoral routes may need to bedeveloped.

Because of the disadvantages of the pre-planned restoral route, it wouldbe desirable to identify a restoral route in real-time when a networkfailure is detected. In this way, the restoral route could be optimizedbased on the current network configuration. However, the identifying ofsuch restoral routes in real-time has been impracticable for severalreasons. First, vast amounts of information need to be culled andprocessed to even determine the current configuration of the network.Second, such vast amounts of information have been typically storedusing database systems that provide only relatively slow access. Third,because a network can have many different types of devices with verydifferent characteristics, the computer programs that access the datarepresenting these characteristics can be very complex and inefficient.Moreover, if a new type of device were added to the network, then thecomputer programs would need to be modified to accommodate the new typeof device.

SUMMARY OF THE INVENTION

The present invention provides a Real-Time Device Data Management(RTNDD) system for managing access to data describing devices in atelecommunications network. The RTNDD system maintains a partition datastructure for each device. The partition data structure has a headersection and a port data section. The header section contains dataelements describing the device (e.g., number of ports and device type).The port data section has a port data structure for each port of thedevice that contains data elements describing the port (e.g., currentcross-connect and actual port address for device). The RTNDD system alsoprovides a standard interface through which external systems access thedevice data. The standard interface has functions for reading andwriting to the partition data structures. Each read function readsmultiple data elements of a header section or a port data structure at atime, and each write function writes a single data element of a deviceat a time. The standard interface is device independent such that anexternal system can use the standard interface to access device data forany type of device whose data is stored in a partition data structure.

The RTNDD system also synchronizes access to the device data whenmultiple external systems are accessing device data concurrently. TheRTNDD system allows multiple external systems to be reading from apartition data structure simultaneously. The RTNDD system also allowsmultiple external systems to be writing to a partition data structuresimultaneously so long as they are not writing to the same data elementof the partition data structure. The RTNDD system uses a lockingmechanism to control synchronization.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating the architecture of the RTNDDsystem and the external systems.

FIG. 2 is a flow diagram illustrating a read function of the StandardInterface.

FIG. 3 is a flow diagram illustrating a write function of the StandardInterface.

FIG. 4 is a block diagram illustrating the use of the RTNDD system by anRTR system.

FIG. 5 is a block diagram illustrating an Update Manager that isresponsible for updating the RTNDD system.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a Real-Time Network Device DataManagement (RTNDD) system that maintains real-time data on currentconfiguration and topology of network switching devices in a way thatincreases system performance and reduces development time and effort foradding new types of devices. The RTNDD system includes a memory-residentdatabase that is accessible to external systems for reading and writingdata relating to the devices in the network. The RTNDD system provides ageneric interface for accessing device data, partitions data byindividual devices for fast access, and organizes data elements withineach partition such that multiple external systems can access data of asingle device simultaneously. The external systems each execute as aseparate process (on the same or a separate computer) and requestservices of the RTNDD through the generic interface that is a set offunctions that execute within each process.

Through the generic interface provided by the Standard Interface of theRTNDD system, external systems can access the data for any type ofdevice in a uniform manner. The RTNDD system encapsulates the datarepresenting any type of device and allows the external systems toaccess the data only through the generic interface. This encapsulationof device data ensures that any changes to the device data structures orthe internal architecture of the RTNDD system is transparent to externalsystems. Thus, the encapsulation not only reduces the time and effortneeded to integrate different types of devices by eliminating the needto modify external systems, but also increases run-time performance byreducing the amount of irrelevant data that external systems need toprocess to perform their function.

The data stored by the RTNDD system is partitioned by the individualdevices. That is, each device has its own partition, and the data forthe device is stored in that partition as data elements. To allow rapidaccess to the partitions, the RTNDD system stores the partitions in anarray. The RTNDD system provides the external systems with indexes intothe array so that a partition can be rapidly accessed when an externalsystem provides the index to the partition for the device whose data isto be accessed. Within each partition, the RTNDD system organizes thedata on a port-by-port basis, which is also indexed for rapid access.

The Standard Interface of the RTNDD system coordinates access to thedata for a device (i.e., a partition) to reduce synchronizationproblems, while at the same time ensuring real-time access to thepartitions. The Standard Interface allows multiple external systems toread a partition simultaneously. The Standard Interface also allowsmultiple external systems to write data to a partition simultaneously.However, to prevent synchronization problems the Standard Interface doesnot allow a read and a write to occur simultaneously and does not allowmultiple writes to the same data element to occur simultaneously. TheStandard Interface provides functions for reading and writing to thepartitions. The functions to read the data return the values formultiple data elements, but the functions that write the data only writea single data element at a time. The Standard Interface uses thefollowing synchronization mechanism to reduce synchronization problems.When an external system invokes a function to read a partition, theStandard Interface determines whether any external system currently hasa write lock on a data element of the partition. If there is a writelock, then the Standard Interface waits until the write lock is removedand then places a read lock on the partition. If there is no write lockon the partition (i.e., no locks or only read locks), the StandardInterface immediately places a read lock on the partition. Once the readlock has been placed, the Standard Interface reads the data of thepartition and then removes the read lock. When an external systeminvokes a function to write a data element, the Standard Interfacedetermines whether there is a read lock on the partition or a write lockon that data element. If either lock is present, the Standard Interfacewaits until the locks are removed and then places a write lock on thedata element. If there is no such lock, then the Standard Interfaceimmediately places a write lock on the data element. Once the write lockhas been placed, the Standard Interface updates the data element andremoves the write lock. The Standard Interface processes the requests toaccess a partition in the order they are received. For example, if afunction to write a data element is received and an external system iscurrently waiting to place a read lock, then the read lock will beplaced before the write lock and the external system requesting thewrite will wait until that read lock is removed.

The device data of the RTNDD system is generally updated by two types ofexternal systems: the network provisioning system (NPS) and the networkdevice interfaces (NDIs). The network provisioning system is responsiblefor identifying each device and setting the interconnectivity of thedevices. The network device interfaces are responsible for updating theinformation relating to their internal configuration, includingcross-connections and software versioning. The other external systems,referred to as client systems, read the data but do not update the datain the partitions.

FIG. 1 is a block diagram illustrating the architecture of the RTNDDsystem and the external systems. The RTNDD system 10 includes a StandardInterface 18, a partition 11 for each device, and an indexing component16. The external systems include client systems 26, the networkprovisioning system (NPS) 24, and the network device interfaces (NDIs)20 that each access the device data using the Standard Interface. Thepartitions are organized into an array, and each partition is dividedinto a Header section 12 and Port Data section 14. The Port Data sectionis organized as an array with a port data structure for each port of thedevice. The indexing component provides a mapping from the system-widename for a device to the index of the partition for that device in thearray of partitions.

Network devices may be any type of telecommunications switching device.The type of device generally depends on the application for which theRTNDD system is used. For example, if the RTNDD system is used by areal-time restoration (RTR) system, then the network devices may beDigital Cross-Connect 3/3 (DXC 3/3) devices. If the RTNDD system is usedby a dynamic call setup system, then the network devices may be DXC 1/0and DXC 1/3 devices.

An NDI is a computer application that serves as the interface betweenthe RTNDD system and the network devices. An NDI is developed for eachtype of device and provides a mapping from the configuration informationstored in the network device to the data stored in the partition. An NDImay execute on the same computer system as the RTNDD system or mayexecute on a separate computer system.

The NDIs provide many functions for the application (e.g., an RTRsystem) using the RTNDD system. The NDIs send commands and auditrequests to the network devices. The network devices respond with auditresults and confirmation of commands executed and supply unsolicitedalarms to the NDIs. The NDIs then update their corresponding partition.For example, the NDI for network device 1 may send a command (e.g.,received from an RTR system) to network device 1 to cross-connect port 1to port 2. Network device 1 would then perform this cross-connect andsend confirmation to the NDI for network device 1. The NDI for networkdevice 1 would then update its partition using the Standard Interface toreflect this new cross-connect.

The RTNDD system maintains a RTNDD Header Section (not shown) thatindicates the current number of partitions maintained by the RTNDDsystem. Each partition consists of a Header section and a Port Datasection. The Header section contains data identifying the device,including an identifier code for the device, a network address, the typeof device, the software version, and other pertinent data. The Headersection also includes specifications for the type of communicationslinks used by the NDI to reach the network device. The Port Data sectioncontains port data for each port of the network device. The port data isstored in an array of port data structures with a port data structurefor each port. The port data includes port type (e.g., DS-1, DS-3,OC-12), state of the port, any alarms on the port, configuration of theport, and other pertinent data. (A DS-n port is one that transmits andreceives electrical signals at a certain digital bit stream rate. AnOC-12 port is one that transmits and receives optical signals, inaccordance with the industry standard for SONET.) The Port Data sectionalso contains data that describes the interconnectivity of networkdevices. Each port data structure identifies those network devices andports to which that port is connected. For example, if port 11 ofnetwork device 1 is connected to port 22 of network device 2, then theport data structure for port 11 of network device 1 identifies port 22of network device 2 and vice versa.

Network devices are usually identified in the network by some codescheme. For example, a network device identifier may be a combination ofa geographic location code, specific device code, and equipment type. Inthis scheme, if the location code of a device is AST, the specificdevice code is AA, and the equipment type is C (which may represent anAlcatel DXC 3/3), the device identifier may be AST₋₋ AA₋₋ C. Externalsystems could use this device identifier when specifying which partitionto access. However, the RTNDD system would need to lookup the index ofthe partition in the array of partitions using the indexing componenteach time it receives the device identifier. The RTNDD system provides afunction that maps the device identifiers to their corresponding index.The external systems can use this function to find the index for adevice. From then on, the external systems can use the index to identifythe partition each time the partition is accessed. In this way, theoverhead of mapping from device identifier to index can be minimized.Similarly, since the port data is also stored in an array, each port canalso be identified by an index into the array. Thus, the port identifiercan be mapped to indexes which can be used by the external systems toavoid the overhead of mapping from port identifier to index.

The client systems are applications that read the data of the RTNDDsystem, but do not directly update the data. These applications caninclude real-time restoration, dynamic call setup, and networkmanagement and monitoring systems. A client system may execute on thesame or different computer as the RTNDD system. The RTNDD system mayservice multiple client systems simultaneously. The generalized mannerin which the RTNDD represents network devices makes it possible fordifferent client systems to use the RTNDD system for different purposes.For example, a real-time restoration system may use the RTNDD system totrack the current configuration of a DXC 3/3 restoration network, whilea dynamic call setup application may use the RTNDD system to track thecurrent configuration of a DXC 1/0 and DXC 3/1 virtual private linenetwork.

The network provisioning system (NPS) is an external system that tracksand maintains overall network topology data. The NPS stores data in itsdatabase to reflect the provisioning of the network. The NPS databasemay contain records that correspond to logical traffic trunks and thatidentify each piece of equipment traversed by a trunk. However, thisorganization of data does not allow for rapid access to data needed byrestoration and dynamic call setup applications. These applications needto access data relating to switching devices and interconnectivity andintraconnectivity of the devices.

The RTNDD system receives selective data from the NPS that reflects theconfiguration and topology of the network devices that are of interestto the client systems. For example, if the RTNDD system is used by areal-time restoration system, it will receive from the NPS data thatidentifies the DXC 3/3 as devices, the configuration and type of eachDXC 3/3, the ports of each DXC 3/3, and the interconnectivity amongvarious DXC 3/3 devices. The RTNDD system stores this data so that itcan be rapidly accessed during real-time restoration. The NPS updatesthe data in real-time. That is, it updates the memory-resident partitionso that an update can be read immediately by client systems.

While there are two external systems that write data to the RTNDDsystem, each one is responsible for updating its own data elements. Thatis, the NPS updates certain data elements and the NPI updates other dataelements. Because only one system preferably updates each data element,these systems do not have to wait while another system updates a dataelement. The NPS 24 initializes all data at startup of the RTNDD system,then updates such data as device type, device address, andinterconnectivity among devices (i.e., which devices are connected towhich devices). The NDI 20 updates port configuration data and internalconnectivity within each device. This scheme ensures no conflicts amongtwo systems writing to the same data element. Because the RTNDD systemplaces write locks on individual data elements, both the NPS and an NDImay write simultaneously to data elements within the same partition, aslong as they are different data elements. This increases systemperformance because one update system does not need to wait for theother update system to finish with a partition (device) before makingupdates to the same partition (device).

Another aspect of the RTNDD 10 that is illustrated in FIG. 1 is the useof a Standard Interface 18. The Standard Interface providesencapsulation of device data and data structure within the RTNDD system,so that devices and RTNDD internal structure are abstracted to externalsystems. The Standard Interface is a set of common functions that areused to read and write data of the RTNDD system. These functionsgeneralize the structure and parameters of the data stored by the RTNDDsystem so that external systems do not need to know the internalstructure. The Standard Interface translates requests for data reads andwrites, which are submitted by external systems in a common format, toactions that are specific to the particular device type that is toreceive the read or write request.

Because the external systems access the RTNDD system only through theStandard Interface, the internal structure of the RTNDD system can bechanged without having to modify the external systems. Similarly, adevice partition can be changed without having to modify externalsystems. For example, if a DXC port changes from a DS-3 port to an OC-12port, a client system that is to read data from that port does not needto be aware of the change. The client system simply requests a read fromport 9, for example, and the Standard Interface translates that requestto the action that is needed for port 9, depending on the type of port.

The encapsulation provided by the Standard Interface also allows for newtypes of devices to be added to the RTNDD system without having tomodify the external systems. For example, if the RTNDD system is setupfor DXC 3/3 devices, and now a DXC 1/0 device is to be added, the clientsystems do not need to know a new structure or set of parameters. Theyuse the same Standard Interface calls to read data. Also, some vendor'sDXC 3/3 devices have 512 ports. Other vendor's devices have 2048 ports.If a client system requests an audit of a particular device's entireport range, it does not need to know how many ports are included, andtherefore what type of device it is. The RTNDD system also abstracts thevarious addressing schemes used by devices. For example, a DS-3 port maybe addressed by a single number (e.g., "5"), and an OC-12 port may beaddressed by a triplet (e.g., "1, 1, 1"). A client system, such as anRTR system, does not need to know what particular addressing scheme isused for a port. Actual port addresses are mapped to generic portnumbers (i.e., indexes) within the RTNDD system. For example, an RTRsystem may send cross-connect commands to network devices via the NDIs.The RTR system may send a command for network device 1 to cross-connectport 7 to port 8, without having to know what types of ports they areand what addressing scheme they use. The NDIs query the RTNDD system forthe actual port address for port 7 and 8 using a Standard Interface. TheRTNDD system retrieves the actual port addresses from port datastructures for ports 7 and 8 and sends the port addresses to the NDI.The NDI then requests the network device to cross connect using theactual port addresses.

The following three functions are the functions of the StandardInterface for reading the data of the RTNDD system. The StandardInterface preferably places read locks not on an entire partition, buton a Header section or on an individual port. In this way, the waitingfor locks to be removed can be minimized. Also, a write to the data ofone port can occur simultaneously with a read to another port of thesame device. The functions return all the data elements for a particularheader or port.

int RTNDD₋₋ Get₋₋ Header₋₋ Data (RTNDD₋₋ leader₋₋ struct *rtndd₋₋header₋₋ data)

This function returns all the data in the RTNDD header.

    __________________________________________________________________________    int RTNDD.sub.-- Get.sub.-- Device.sub.-- Header.sub.-- Data                                    (short       device.sub.-- num,                                               Device.sub.-- Header.sub.-- Data.sub.-- struct                                             *device.sub.-- header.sub.-- data)             __________________________________________________________________________

This function returns all data for the specified device.

    __________________________________________________________________________    int RTNDD.sub.-- Get.sub.-- Device.sub.-- Port.sub.-- Data                                      (short      device.sub.-- num,                                                unsigned short                                                                            port.sub.-- num,                                                  Device.sub.-- Port.sub.-- Data.sub.-- struct                                              *device.sub.-- port.sub.-- data)                __________________________________________________________________________

This function returns all the port data for the specified port of thespecified device.

The following functions are sample functions of the Standard Interfacefor writing data to the RTNDD system. The Standard Interface has a writefunction for each data element in the RTNDD Header section, the Headersection, and the Port Data section. The Standard Interface places writelocks on individual data elements.

    ______________________________________                                        int RTNDD.sub.-- Set.sub.-- Port.sub.-- Type                                                    (short      device.sub.-- num,                                                unsigned short                                                                            port.sub.-- num,                                                  PORT.sub.-- TYPE                                                                          port.sub.-- type)                               ______________________________________                                    

This function sets the port type of the specified port of the specifieddevice. This function is invoked by the NPS.

    __________________________________________________________________________    int RTNDD.sub.-- Set.sub.-- Current.sub.-- Cross.sub.-- Conn                                     (short  device.sub.-- num.                                                    unsigned short                                                                        port.sub.-- num,                                                      int     cross.sub.-- conn.sub.-- index,                                       short   current.sub.-- cross.sub.-- connect)               __________________________________________________________________________

This function sets the current cross connection for the specified portof the specified device. This function is invoked by an NDI.

FIG. 2 is a flow diagram illustrating a read function of the StandardInterface. The read functions set a lock on the appropriate section orport, read the data from that section or port, and then remove the lock.In step 201, the read function places a read lock on the section orport. The lock is not placed until no write lock is currently pending onthat section or port. In step 202, if a time out occurs before the lockis placed, then the read function returns a time out indication, elsethe read function continues at step 203. In step 203, the read functionreads all the data elements from the section or port. In step 204, theread function removes the lock from the section or port and returns anindication that the read was successful.

FIG. 3 is a flow diagram illustrating a write function of the StandardInterface. The write functions place a lock on the individual dataelement to be written, write the data element, and then remove the lockfrom the data element. In step 301, the write function places a writelock on the data element to be updated. The write lock is not placeduntil all read locks have been removed from the section or port thatcontains the data element and until any write lock on that data elementhas been removed. In step 302, if a time out occurs, then the writefunction returns a time out indication, else the write functioncontinues at step 303. In step 303, the write function writes the dataelement. In step 304, the write function removes the write lock andreturns an indication that the write was successful.

FIG. 4 is a block diagram illustrating the use of the RTNDD system by anRTR system. In this example, the RTNDD system 26 is notified of anetwork failure by NDIs 20, and then accesses the RTNDD system 10 todetermine the current configuration of the network. The RTR systemidentifies a restoral route to bypass the failure and sends commands tothe NDIs to implement the restoral route. The NDIs send commands to thenetwork devices 22 to implement the restoral route and also updates theRTNDD system to reflect the new configuration. The network devicesgenerate an alarm when a failure occurs and sends 401 the alarm to theNDIs. When an NDI receives an alarm, it updates 402 the RTNDD system toindicate that an alarm has been received for a specific port of aspecific device. The NDI then forwards 403 the alarm to the RTR system.The RTR system, when it receives an indication of the alarm, queries 404the RTNDD system to determine the current state and configuration of thenetwork devices that are either impacted by the failure or will beinvolved in the restoral route. The RTR system then identifies therestoral route and sends 405 commands to the NDIs to implement therestoral route. The commands identify the network devices and portsusing the indexes of the RTNDD system. When the NDIs receive thecommands, they query 406 the RTNDD system to determine the actualnetwork address of the network devices and port addresses of the ports.The NDIs then send 407 the restoral route commands to the networkdevices. When the network devices complete processing the commands, thenetwork devices respond 408 to the NDIs with a confirmation that thecommands have been completed. The NDIs then update 409 the RTNDD systemto reflect the new configuration of the network devices. The NDIs alsonotify 410 the RTR system that the command has been completed.

FIG. 5 is a block diagram illustrating an Update Manager that isresponsible for updating the RTNDD system. The Update Manager, which ispart of a client system such as an RTR system, coordinates updates tothe RTNDD system. When the client system is started, the partitions ofthe RTNDD system 10 are loaded into memory from the NPS 24 data. TheNDIs 20 then perform a routine audit of the network devices 22. Thisaudit determines the network devices that are on line and theconfiguration of their ports. If the NDIs receive an audit response thatreflects a configuration that is different than what is stored in theRTNDD system, the NDIs notify the Update Manager 28 so that theinconsistent states can be resolved. On startup, the NDIs issue 501 anaudit request to the network devices. The network devices responds 502with an audit of their ports. The NDIs then update 503 the RTNDD systemwith the data from the audit. The NDIs also check the data elements forwhich the NPS is responsible for updating. If that data element does notaccurately reflect the audit, the NDI notifies 504 the Update Managerthat data elements for which the NPS is responsible require updating.The NPS notifies 505 the Update Manager of updates to the networktopology. The Update Manager updates 506 the RTNDD system based oninformation provided by the NDIs and the NPS. The Update Manager updatesthe RTNDD system based on whether the NDIs are to override the NPS, orvice versa.

The following tables describe the data elements of the RTNDD Headersection, the Header section, and Port Data section.

    ______________________________________                                        RTNDD HEADER                                                                  NAME           DESCRIPTION                                                    ______________________________________                                        Maximum potential devices                                                                    The maximum possible number of                                                devices.                                                       Maximum configured devices                                                                   The actual number of configured devices.                       Start of Header sections                                                                     Starting index, lookup table, jump table,                                     or other data structure to allow the                                          Standard Interface to know the                                                starting address.                                              ______________________________________                                    

    ______________________________________                                        DEVICE HEADER                                                                 NAME        DESCRIPTION                                                       ______________________________________                                        Device entry status                                                                       Indicates the presence or absence of valid data                               within this partition.                                            Station Code                                                                              MECCA/RTT provided station code                                   Equipment Code                                                                            MECCA/RTT provided equipment code                                 Device Specifier                                                                          The Station Id, the Equipment alpha, and the                      Structure   equipment id strings.                                             Station id  MECCA/RTT provided station name                                   Equip Alpha MECCA/RTT provided equip alpha                                    Equip Id    MECCA/RTT provided equipment id                                   Active Links                                                                              Indicates which of the two binary links (in the                               Binary Link Specification Structure) contains                                 valid data and should be used by the NIFTE to                                 establish communication to the device.                            Binary Link The complete specification and status for a binary                Specification Structure                                                                   links. There is a Binary Link Specification                                   structure for each binary link.                                   Network Name                                                                              The name of the network to utilize for this binary                            link                                                              NIS Name    The name of the Network Interface Device,                                     (DECNIS, or Switch) to which X.25 Calls are                                   made.                                                             Local DTE Address                                                                         Local DTE address on host side.                                   Direct Connect                                                                            Indicates whether the connection is made directly                             or through a remote interface.                                    Remote DTE  Remote DTE address on target side.                                Address                                                                       Number of Virtual                                                                         Number of virtual links for this binary link.                     Links                                                                         Virtual Link                                                                              The specification for each virtual link as well as                Specification                                                                             the link's current state and status.                              Structure                                                                     Virtual Link Type                                                                         Virtual link type name.                                           Virtual Link                                                                              The current status of the link.                                   Status                                                                        Virtual Link State                                                                        The current state of the virtual link.                            Permanent Virtual                                                                         A unique number that identifies the PVC.                          Circuit (PVC)                                                                 Number                                                                        Number of   Number of connection attempts that have been                      Connect Attempts                                                                          made since the last successful connection.                        Maximum Device Port                                                                       The maximum numerical device port # value                         Used        which would be "of interest to" a real-time                                   restoration system. "Of interest to" means that                               it is TRAFFIC.sub.-- BEARING or SPARE.                                        PROTECTED or NOT.sub.-- PROVISIONED ports                                     are not included in the calculation of this value.                Maximum Device Port                                                                       The maximum possible number of ports.                             Capacity                                                                      Maximum Device Port                                                                       The maximum numerical device port # value                         Number In Use                                                                             which would be of interest to a real-time                                     restoration system.                                               Device Node Id                                                                            This value contains the device node number                                    assigned by the real-time restoration system.                                 Note that for DSC device, the max value is 255,                               whereas for Alcatel devices, the max value                                    is 65535.                                                         Is NIFTE Running                                                                          This value is set by the NIFTE as soon as it starts               Flag        running, and is turned off by the NIFTE when                                  it terminates.                                                    Start Of Elements For                                                                     Location of port data structures.                                 This Device                                                                   ______________________________________                                    

    ______________________________________                                        DEVICE PORT DATA                                                              NAME        DESCRIPTION                                                       ______________________________________                                        Port provisioning                                                                         Indicates how the port has been provisioned by                                field engineers.                                                  RTR allocation status                                                                     The current status of the port as determined by the                           Route Generator. This value is only read and                                  written by Route Generator.                                       Port Type   The hardware facility type for which this port is                             configured                                                        Port Address                                                                              Actual device port address.                                       Signal clocking                                                                           The type of signal clocking used by the trunk;                                DS3's are always ASYNC, ECls can be SYNC                                      or ASYNC.                                                         Provisioned cross                                                                         The device internal port cross connection.                        connection                                                                    Number of Broadcast                                                                       Indicates whether this port is internally cross                   Ports       connected to 0, 1, or 2 other ports. This value                               serves as an index though the API to look up the                              actual cross-connect values.                                      Current cross                                                                             The device internal port cross connection.                        connection                                                                    Remote end Device #                                                                       The remote device number to which this port and                               trunk are connected.                                              Remote end Device                                                                         The remote port number to which this port and                     port #      trunk are connected.                                              Last Alarm Update                                                                         The last time that this port was updated with                                 alarm data.                                                       Last Configuration                                                                        The last time that this port was updated with                     Update      configuration data.                                               Last Connect Update                                                                       The last time that this port was updated with                                 connect data.                                                     Port Alarm State                                                                          The current alarm state of the port.                              Break ID    The event of a preplan, or a RTR Route Generator                              assigned Break Id in the event of Dynamic route                               generation.                                                       Trunk ID    The MECCA assigned trunk id for the trunk                                     which connects to this port.                                      Trunk Priority                                                                            Relative importance of the trunk as it pertains to                            restoration. Restoration will be attempted on                                 trunks with higher priority before trunks with                                lower priorities.                                                 Port Configuration                                                                        The port configuration state as the Device knows                  State       it.                                                               ______________________________________                                    

Although the present invention has been described in terms of apreferred embodiment, it is not intended that the invention be limitedto these embodiments. Modifications within the spirit of the inventionwill be apparent to those skilled in the art. The scope of the presentinvention is defined by the claims that follow.

What is claimed is:
 1. A system for accessing data describing aplurality of network devices, comprising:a data structure containingdata describing each of the plurality of network devices, each networkdevice having a network device type; wherein the data structure has onepartition for each network device, wherein the partitions are stored inan array, and wherein each partition is identified by an index into thearray and wherein each network device has ports and each partition has aheader section for storing data that is not port specific and a portdata section for storing data describing the ports; a standard interfacefor providing a common mechanism for accessing the data structure toread and write the data describing the network devices; a plurality ofexternal systems that use the standard interface to access the datadescribing the network devices; and whereby data describing networkdevices of new types can be added to the data structure and accessed bythe external systems without modify the external systems.
 2. The systemof claim 1 wherein the standard interface provides a mapping betweengeneric port addresses to actual addresses used by the network devices.3. The system of claim 1 wherein the standard interface providesfunctions for reading and writing the data and wherein the externalsystems invoke these functions to access the data.
 4. The system ofclaim 1 wherein the standard interface allows multiple external systemsto be simultaneously reading data for the same network device and allowsmultiple external systems to be simultaneously writing data for the samenetwork device.
 5. The system of claim 1 wherein the data structure isstored in primary storage of a computer system for rapid access byexternal systems.
 6. The system of claim 1 wherein each data element ofthe data is updated by only one external system to minimize waiting whenupdating the data.